Flat spot at 3k RPM?

S

sbtwister

Active member
 Santa Barbara, CA
Anyone ever experience an acceleration flat spot at 3k RPM? I occasionally experience this (1 -2 times per day), but not all the time, only in 2nd gear (Auto trans in manual mode w sport botton ON) and only at 3000RPM. Always fine in every other gear, no other problems at all. It has been very difficult to chatacterize, does not depend acceleration rate, it just shows up as a slight flat spot, then accelerates right thru.
Car is in at the dealer right now, for final check before Manufacturers warranty expires (still covered by CPO), but I doubt they will be able to identify, or possibly even reproduce.
 
Mine kinda hesitates at 3k rpm too (altho a different engine) but have always just assumed this to be a characteristic of the VANOS. Anyone else with the 3.0 wanna confirm?
 
What throttle loadings does it do this? Sounds like the VANOS could be on its way out but it could be so many other things (Lambda 1 if at part throttle or maybe the inlet camsghaft sensor), how many miles has the car done?

Mine previously did this terribly in all gears. What fixed it for me is fill with high octane fuel (tesco 99), reset ecu (battery off for 15 mins) and then drive like you stole it :thumbsup: Sometimes i think the fuel tables and throttlebody data gets a little mixed up :)

Edit: if you cant be bothered to take the battery off just try a Throttlebody reset:
http://www.z4-forum.com/forum/viewtopic.php?f=32&t=195&p=215664&hilit=throttle+body+reset#p215664
 
My car's got just over 24k miles on it. I've never noticed this flat spot under heavy acceleration, just seems to come occasionally during normal driving.
Had it in to the dealer yesterday - cause factory warranty runs out at the end of the week (CPO kicks in for another 2 years). Dealer gave it the once over, checked it out on the computer diagnostics, but all they could come up with was a loose air intake hose clamp.
Good news is that the issue is on the record now, and the check out of the car was gratis! They did offer to extend the Factory warranty for the length of the CPO warranty, for $1900! With the low miles Iput on the car, I think I'll let that one pass....
 
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